1. Field of the Invention
The present invention relates to a sensing amplifier using capacitive coupling to realize a dynamic reference voltage, and more particularly to a sensing amplifier which effectively enhances the sensing margin of a sensing amplifier circuit; and in addition accelerates access speed. The sensing amplifier can easily determine the correct stored data and further quickly solve the problems of high-speed storing data by storage units.
2. Description of Related Art
With the rapid development of science and technology in the modern era, non-volatile memories, such as flash memory, have been widely used in a variety of electronic products. Traditionally, the stored data in a memory cell of the flash memory is read through a column decoder and a row decoder to a memory cell and applies with the memory a bias for comparison between the sensed current and a reference voltage through a sensing amplifier circuit which accordingly judges the stored data.
With the more advanced process technologies with increasingly high integration, the size of the supply voltage for the flash memory decreases accordingly so that the flash memory has lower power consumption and higher access speed.
However, since such a reduced supply voltage will lead to a lower sensing margin for the sensing amplifier circuit, so that the sensing amplifier circuit tends to make mistakes in determining the stored data. For such a problem encountered in processing data stored by storage units in a conventional sensing amplifier circuit, it is assumed that the sensing margin is 80 Mv. When it reads a 0, the bit line needs to reduce to 160 mV to ensure the success in sensing. The long sensing time causes the shortcoming of being time-consuming. The reduced sensing margin leads to less reading reliability. Furthermore, when it reads a 0, the data line (DL) drops and the mos N1 becomes weak, eventually making the VREF to increase. Even though the technology allows the DL to drop only to 80 mV through its feedback system and ensure success in sensing. However, the processing speed is not enough for the needs of high-speed reading. The needs of high-speed and effectively enhancing the accuracy of data sensing for the sensing amplifier circuit is still not met.
For this reason, the inventors has studied and proceeded in-depth discussion, and actively seek approaches for many years engaged in the research and experiences of related industries and manufacturing. After long-term research and efforts in development, the inventors have finally successfully developed this invention ‘sensing amplifier using the capacitive coupling to realize the dynamic reference voltage’ which overcomes the shortages in the prior art.